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. Author manuscript; available in PMC: 2018 Mar 29.
Published in final edited form as: Cell. 2014 Jul 17;158(2):237–238. doi: 10.1016/j.cell.2014.07.004

Figure 1. The Epigenetic versus Genetic Routes of Lamarckian Evolution.

Figure 1

(A) The genetic mechanism. This route of Lamarckian evolution is illustrated using the case of the CRISPR-cas system. R, repeat; S, spacer (denoted protospacer in foreign DNA). The insertion of a new spacer is accompanied by repeat duplication. Cas1-Cas2, complex of two Cas protein that is involved in the excision of the protospacer from theforeign DNA and itsinsertion between repeats at the end of the CRISPR cassette. (B) The epigenetic mechanism. Assimilation is denoted by a broken arrow to emphasize that this is not a well-characterized process.